The BBC’s ‘Planet Earth II,’ deployed 60 cameramen in 40 countries for more than 2,000 days

One of the most memorable chase scenes you’ll see on screen this year—vehicular, human or other—unfolds on a rocky Galapagos beach, as freshly hatched iguanas try to outsprint gangs of swift, long snakes.

This sequence from “Planet Earth II,” starting Feb. 18 on BBC America, went viral on the web and helped drive record ratings for the...